<!DOCTYP html>
<html>
    <head>
        <meta  charset="utf-8">
         <title>网页标签</title>
        <style>
     #grad1 {
    height: 150px;
    width: 200px;
    background-color: red; 
    background-image: radial-gradient(red, green, blue); 
    </style>
    </head>
    <body>
<div id="grad1"></div>
<p><strong></strong>有部分版本不支持渐变 </p>
</div>
        <h1>我是张国艳的第一个网页</h>
        <h2>CSS 按钮</h2>
<button>默认按钮</button>
<a href="#" class="button">链接按钮</a>
<button class="button">按钮</button>
<input type="button" class="button" value="输入框按钮">
       <p> 我是第一个网页</p>
       <p>我是修改后网页</p>
<body>
<div class="wrapper">
  <div id="leftsidebar">
    <ul id="menulist">
      <li class="menuitem">Menu-item 1</li>
      <li class="menuitem">Menu-item 2</li>
      <li class="menuitem">Menu-item 3</li>
      <li class="menuitem">Menu-item 4</li>
      <li class="menuitem">Menu-item 5</li>
   </ul>
  </div>
  <div id="main">
    <h3>窗口查看效果！</h3>
  </div>
</div>
    </body>
</html> 